Question

Clarissa Clifton is a 20-something woman who spent much of the spring day working in her garden. A blustery wind caused her to unintentionally inhale the insecticide that she was spraying throughout the garden. When she began wheezing severely, she was taken to the emergency room!

The attending physician observed other symptoms including:

• Constricted pupils
• Bradycardia (slowed heart rate)

The physician prescribed administration of intravenous atropine sulfate.

1. Which division of the autonomic nervous system that releases acetylcholine (Ach) onto target effectors, is most affected in this case? Name the type of autonomic receptor that binds to Ach versus Norepinephrine. What are the subclasses for each receptor type?
   1. Atropine sulfate is the antagonist of cholinergic system. Cholinergic system is also called as Parasympathetic system. It uses Acetylcholine both as the preganglionic neurotransmitter as well as postganglionic neurotransmitter. There are two types of receptors of the parasympathetic system to where Acetylcholine binds:- muscarinic and nicotinic. Norepinephrine belongs to sympathetic system which has alpha and beta receptors. Muscarinic receptors are of 5 types:- M1, M2, M3,M4,M5. M1 act mainly on the autonomic ganglia and gastric glands. M2 receptors are mainly present on heart. M3 receptors on bronchioles, gastric smooth muscles, iris. M4 and M5 are present in CNS. Nicotinic receptors are of two types:- Nm type (neuromuscular junction) and Nn type (autonomic ganglia).
2. Insecticides contain organophosphates which inhibit acetylcholinesterase. What is the function of this enzyme? Are receptors you listed in #1 more likely to be over or under-stimulated as a result of inhaling insecticides?
   1. Organophosphates are the anticholinesterases. Cholinesterase is an enzyme which is used to hydrolyze the Acetylcholine molecule. It decreases the concentration of Acetylcholine in the synaptic cleft. Anticholinesterases inhibit the enzyme Cholinesterase and lead to increased concentration of Acetylcholine in the synaptic cleft. It leads to prolonged action of parasympathetic system. The receptors will be overstimulated as Acetylcholine remains in the synaptic cleft for long and in high concentration.
3. What are some general physiological behaviors that occur under each division of the ANS (hint what are the sayings we use to describe them)? Do the medical observations made of Clarissa support your answer to #2? Explain why/why not.
4. How would insecticides impact motor activity in the following systems or organs?
   1. Gastrointestinal tract -
   2. Sweat glands -
   3. Bronchioles (airway) -
   4. Coronary vessels (blood vessels supplying heart muscle) –

Need 3 and 4 answered (1 and 2 are answered (hopefully) correctly)

Answer 1

ANS (Autonomic Nervous System) acts independently of body's consciousness and voluntary control

ANS has two sub divisions:

1. SYMPATHETIC NERVOUS SYSTEM (SNS)
2. PARA SYMPATHETIC NERVOUS SYSTEM (PSNS)

SYMPATHETIC:

In our body sympathetic system gets activated in situations that require ALERTNESS and ENERGY i.e, whenever our body is in danger or doing some energy consuming works like exercise etc.!

Whenever there is activation of sympathetic system following changes happen

• cardiac output increases (Heart rate also increases)
• Respiratory rate increases
• Dilatation of Pupils
• Utilisation of stored energy
• inhibition of less important body processes like digestion, urination etc.!

PARASYMPATHETIC

Following features are seen parasympathetic activity which are exactly opposite to sympathetic system.

• Decreased cardiac output ( Heart rate also decreases)
• Decreased respiratory rate
• Digestion and urination
• smooth muscle contraction
• Constriction of pupils
• increased glandular secretion ( salivary,digestive system glands etc.!)

​​​​​​​So, simply you can remember sympathetic system activation in FIGHT AND FLIGHT situations and Parasympathetic functions as REST AND DIGEST.

yes, medical observations made in clarissa's case support answer #2

Due to excessive Parasympathetic activity there is Bronchial smooth muscle contraction and increased bronchial secretions which is responsible for the WHEEZE

Contraction of circular muscles in the eye is responsible for PUPILLARY CONSTRICTION

BRADYCARDIA is also seen due to excessive Parasympathetic activity via M2 receptors present on the heart.

4) ORGANO PHOSPATES are the chief components of most of the insecticides and whenever these organo phospates enter the body they block ACETYLCHOLINE ESTERASE, an enzyme which metabolises Ach.

Due to blockage of ACh esterase , the levels of ACh in the synapse increases causing excessive Parasympathetic activity.

• GIT : Due to excessive Parasympathetic activity there will be contraction of smooth muscles in the GIT and increased secretion of GI glands
• CORONARY VESSELS : Parasympathetic system stimulates the endothelial cells to release NO ( nitric oxide) which is a vasodilator So, there will be coronary vessel dilation .

​​​​​​​​​​​​​​I'll type remaining answer in comments, sorry for the inconvinience :(:(